Ranger simply couldn’t see the point of estimating and rounding numbers.

Math is generally an easy subject for him, but he and I hit a roadblock when it came to this concept. Sure, 500 + 600 = 1100 is easy to add in your head—but not all that much harder than 526 + 587 = 1,113, right? He wanted to skip the fiddly imprecise stuff and just work with the real numbers. Nothing I said persuaded him that the skills were useful.

That changed when he had to provide a meal for our family.

As a refresher, Ranger is my youngest child. At 10 years old, he’s not in charge of family meals. All I wanted was for him to work problems 1–4 in his math book, for heaven’s sake. But his Cub Scout troop gave him the chance to earn a badge: he was to plan, shop for, and cook a family meal. It had to cost him under $20, with special recognition for those who came the closest to $13 without going over. It was a challenge, and Ranger is always up for a challenge. He was here for this.

He and I sat down together and planned a menu that he could handle with my help: angel hair pasta, bacon, carrot sticks, store-bought Italian bread, and ice cream. Since we didn’t know how much his chosen ingredients cost, we had to—you know—estimate it. And then we—imagine that!—rounded off those prices for convenience. Ranger quickly saw the benefit in working with 0 and 5 when we didn’t know exact figures.

When we were ready to do the actual shopping, we opened the grocery store’s online shopping app. Here, everything is listed with its current price. Ranger discovered the excitement that comes with that red all-caps word SALE! He also learned to lower his standards for the good of his goal. He chose the (SALE!) $1 Italian bread over the $3.99 ciabatta bread to save money. But he decided to stay with half a cup of ice cream instead of a fourth-cup, because who wants to skimp on ice cream?

Even with the exact prices in front of us, Ranger wasn’t done with estimation: we had tax to account for. We rounded it off at $.50, and then looked at our total. Ranger’s meal came to $13.57. He was disappointed that he didn’t come in under his goal. I pointed out that he was feeding six adult-sized people, and this was a darn good price.

And it was a darn good math lesson, too. Ranger finally concedes that estimation and rounding is useful under some circumstances. His attitude was definitely softened by the badge he proudly earned by shopping, cooking, and serving his family a full meal.

The project was, in his estimation, roundly successful.


Photo credit: iStock